Perrin & Anor v Northampton Borough Council & Ors

For the exemption in section 198(6)(b) of the Town and Country Planning Act 1990 to apply, the nuisance must be actionable, involving actual or imminent damage rather than mere root or branch encroachment. Whether work to a protected tree is necessary is a question of fact, assessed by the everyday sensible approach of a prudent citizen. The word “necessary” concerns the extent of tree work required to prevent or abate the nuisance. It does not require consideration of alternative engineering works, costs, insurance, financial circumstances, amenity value or other wider factors. However, the work must be the minimum necessary. The availability of underpinning or a root barrier therefore does not, by itself, prevent reliance on the statutory exemption.

The claimants’ house had allegedly suffered subsidence damage from the roots of an oak tree protected by a tree preservation order. Their application to fell the tree had been refused by the local authority, and their appeal to the Secretary of State had failed. The claimants sought a declaration that section 198(6)(b) permitted them to cut down the tree to prevent or abate the nuisance.

For the preliminary issue, it was assumed that the tree caused a nuisance, that tree work would prevent or abate it, and that alternative works such as underpinning or a root barrier could also do so. The central issue was whether those alternative works were relevant to the meaning of “necessary” in section 198(6)(b).

1. Construction of nuisance. The reference to nuisance in section 198(6)(b) means actionable nuisance. Actual damage, or damage which will imminently occur if no action is taken, is required. Mere encroachment of roots or branches is insufficient. The statutory works are wider than the common-law right to remove encroaching roots or branches from one’s own land, and the provision also permits prevention of a nuisance.
2. Question of fact. Whether tree work is necessary is determined by an everyday sensible approach, asking whether a prudent citizen could properly say that the work is necessary to prevent or abate the actionable nuisance.
3. Scope of “necessary”. The word provides a link between the tree work specified in the subsection and prevention or abatement of the nuisance. It governs the extent of the work to the tree. It does not introduce a general assessment of reasonableness or require consideration of alternative engineering schemes, comparative cost, financial or insurance circumstances, the tree’s amenity value, or the extent of the nuisance.
4. Minimum work required. The work must be the minimum necessary to prevent or abate the nuisance. If lopping would suffice, uprooting the whole tree would fall outside the exemption and could constitute an offence under section 210.
5. The court distinguished the statutory consent procedure from the section 198(6)(b) exemption. Amenity, alternative works and other wider factors may be relevant to an application for consent, but not to the separate statutory exemption. The preliminary issue was answered affirmatively: the possibility of alternative engineering works was irrelevant on the assumed facts.